Some golf balls comprise a core and an outer cover comprising a polymer layer. A polymer layer of a golf ball can be applied using an injection molding process. In such a process, a golf ball core is typically retained by core pins within a mold cavity, and polymer is injected into an open volume between walls of the cavity and the golf ball core, thereby forming the polymer layer. In some systems, the outer polymer layer is cured or crosslinked to provide greater structural integrity. Conventional post-injection curing or crosslinking, however, undesirably requires that the molded articles be transferred from the original mold system to a different location for curing and/or crosslinking. Improved systems and methods of forming golf balls that reduce or eliminate the need for a remote curing or crosslinking step are desirable.